2015 Ridley Helium SL Frameset

Shedding the grams from a frame design in the name of creating an ultralight deluxe-o-matic whatever model often results in either a flimsy, flexy frameset that's too easy to overpower, or a stiff, jittery one that's lost its ride quality — thankfully, the engineers who designed the Ridley Helium SL knew not to mess with a good thing. The SL is a "Super Light" version of the a famous Helium that doesn't give up a bit of the original's ride quality or stiffness. It's a great frame that needed no adjustment, which is why we're happy that the 2015 model's differences compared to the 2014 model are cosmetic and nothing more.

So how light is light? And how does it ride? These are the two questions we'll address. Starting with weight, the SL is a mere 1050 grams, including frame and fork. With the 300g fork, this leaves just 750 grams for the frame. This was achieved through the use of a sophisticated carbon selection, utilizing a strategic placement of 60, 40, and 30 ton high-modulus carbon fiber. Before the SL, the Helium featured a predominantly 30 ton carbon composition. Why is this important? The "ton" designation in "60 ton" refers to the carbon's ability to withstand 60 tons of pressure per square millimeter. Basic logic tells us that a stronger carbon fiber requires less carbon to be used. In addition, on top of the carbon, Ridley bonded an ultra strong nano-resin that meant it could use less carbon, decreasing overall weight while boosting toughness and stiffness further.

But Ridley's engineers weren't done yet. To further reduce weight, they constructed the front triangle of the SL with a monocoque design. This means that the entire front triangle (head tube, down tube, seat tube, and bottom bracket lug) is made in one piece. How does this save weight? Well, the seatstays, chainstays, and dropouts are bonded to the existing triangle by applying resin and then over-wrapping the bonding points with more carbon fiber. With the SL, this application only occurs once, and you can imagine the added weight of repeating this process at every tube juncture of the frame. Furthermore, Ridley shaved grams by giving the SL a slightly smaller head tube dimension than the Helium, with a 1-1/8 x 1-1/4in tapered design instead of the Helium's 1-1/8 x 1-1/2in.

The SL has also received a new tube shape design. The SL takes its design inspiration from the circle. Yes, the circle. You've probably seen this on the Helium, but the SL does away with the massive, oversized tubing. It features rounded tubing emanating from the seat tube juncture, which slowly becomes box-shaped as it approaches the head tube and bottom bracket junctures. As Ridley puts it, this system creates a clean transition from stiffness to comfort. Supporting this ideology, the rear triangle has been designed to intermix the two. The asymmetric, flat chainstays provide a stiff platform for power transfer to the rear wheel. Meanwhile, the ultra-thin seatstays create a vertically compliant ride quality without sacrificing rigidity.  

And on the subject of rigidity, even though it's a lightweight, Ridley says that the SL is actually stiffer than the Helium. To be exact, Ridley's testing has concluded that the SL is 8% stiffer at the bottom bracket, 4% stiffer at the head tube, and the new fork design not only weighs 90 grams less, but it also has a 20% increased side stiffness. How does this translate to speed? In rudimentary terms, ride quality hinges on what's called a stiffness-to-weight ratio, or specific modulus. And while the mathematics behind the determination of specific modulus are too complicated to explain here, it's not a complicated notion to grasp that a frame with low weight and higher stiffness will efficiently transfer power.

Ridley has also made the SL what it calls "future ready." This is a fancy way to say that its 100% internal cable routing has been designed to accommodate both electronic and mechanical shift systems. And in the case of the seatpost, the SL features a 27.2mm post. This moves away from the ever popular integrated seatposts — saving weight and making packing easier.